F.A.Q. - Frequently asked questions about electricity in boats.
Here you will find answers to questions about charging lithium batteries, charging with alternators, charging with solar cells and other related questions that arise. All information is based on our own experience.
Lithium Batteries
As consumer batteries, lithium batteries are significantly better than AGM, GEL or other lead-based batteries. They last much longer and can be fully discharged thousands of times without damage. The voltage stays high during use and you get the full capacity.
Lithium batteries are a very good investment.
They cost more but they also last for years. Example: 200 AH AGM battery can easily be replaced with a 100 Ah lithium battery.
The oldest Makspower lithium batteries were delivered in 2013. No customers have reported any weakening of the batteries.
AGM and GEL batteries are unpredictable and can break after a full discharge or two.
AGM and GEL batteries from reputable manufacturers aren't cheap and you never know how long they'll last.
For some, AGM and GEL batteries are a straightforward solution.
If you want twice the capacity in the same space and half the weight, Lithium batteries are the solution.
If you invest in lithium batteries, you're guaranteed to get a significantly better experience and much more profitability than buying lead-based batteries.
AGM and GEL batteries can generally be charged with 0.2 C.
Makspower lithium batteries can be charged with 1 C or more.
This means that a 100 Ah GEL or AGM battery is recommended to be charged with 20 amps. The resistance in lead-based batteries increases rapidly and charging, as most people have experienced, is very slow.
A 100 Ah lithium battery can be charged much faster. Cheap lithium batteries have cheap electronics and can be charged relatively quickly.
Makspower 100 Ah lithium batteries can be charged with 100 amps or more, depending on which battery you choose.
If you have a powerful charging source, you can charge your lithium batteries incredibly quickly. We have charged Makspower 100 Ah lithium batteries from empty to 100% full in 74 minutes. Lead-acid batteries don't have a similar capability.
It is difficult to compare Makspower lithium batteries with other lithium batteries. What we can say is that the failure rate of Makspower lithium batteries is virtually zero. Even the oldest Makspower lithium batteries, which are now (in 2024) 11 years old, are alive and well.
No customers have reported weaknesses or reduced capacity regardless of how long they have used the batteries.
There are cheap lithium batteries on the market. Our factory refuses to compromise on quality and produce lithium batteries with cheap cells and components to bring the price down.
We agree with this philosophy. We also have virtually no complaints. That means our customers have great experiences and lasting solutions
Some players in the market stubbornly claim that one type of cell is better than the other.
It's like saying that Elon Musk has chosen the wrong type of cell for his cars. Cylindrical cells have been produced for several decades and are by far the world's most produced cell type. Prismatic cells are a more recent design and are used in BMW's electric cars, for example.
Some also claim that batteries with cylindrical cells have many solder joints that can come loose. The cells are not soldered but welded together. Cylindrical cells are found in all kinds of rechargeable tools and equipment that are thrown around. Have you ever experienced that the battery pack has fallen apart?
What determines the quality is not whether the cells are cylindrical or prismatic, but the quality of the cells and how the cells are mounted in the battery case and the quality of the cells.
Claiming that one type of cell is better than the other we consider propaganda and not neutral product information.
Lithium iron phosphate or also called LiFePO4 batteries
is considered to be one of the safest in battery technology. Google yourself and see what you can find.
In some cases, Lithium Iron Phosphate batteries are confused with Lithium Ion batteries or other types of lithium batteries that are far more unstable.
In mobile phones, PCs, powerbanks and many other products, other battery chemistries are used that are more unstable than lithium iron phosphate batteries.
In the vast majority of Makspower lithium batteries you will find cylindrical cells in A grade or A grade +.
All cells are tested and matched to be virtually identical for maximum performance.
The cells are placed in cell holders to keep them stable.
The result of the very best cells and solid casing is that the batteries appear to have a very long life.
Makspower also has batteries with A grade prismatic cells. We see no difference in quality, lifetime or usage experiences.
As long as we only use the very best cells we can get our hands on, cell type is nothing to worry about as long as you shop at Makspower.
As long as we're talking about Lithium Iron Phosphate batteries LiFePo4, the chance of them catching fire by themselves is approximately zero.
If lithium iron phosphates are exposed to 3-400 degrees of heat, they catch fire and cannot be extinguished. They burn out on their own.
If your lithium batteries catch fire, it's probably due to a fire around the batteries. In that case, you already have a problem and should seek safety immediately.
From Chatgpt:
For lithium iron phosphate (LiFePO₄) cells, spontaneous combustion is very rare compared to other types of lithium-ion batteries, such as lithium cobalt oxide (LiCoO₂). However, extreme overcharging can cause thermal runaway, which can lead to spontaneous combustion.
Self-ignition in LiFePO₄ cells will usually not occur until the voltage per cell is significantly higher than the normal maximum charging voltage. Research and experience suggests that this voltage must exceed 4.5-5.2 V per cell, 18 to 20.8 volts on the battery, before there is a real risk of self-ignition. At these levels, the electrolyte will begin to break down, which can lead to gas formation, build-up of internal pressure, and eventually ignition.
However, this is dependent on several factors, such as temperature, cell quality and how quickly the overcharge occurs. LiFePO₄ is generally more thermally stable and less prone to hazardous behavior than other lithium-ion chemistries, but safety margins should still be carefully observed.
The main choice is whether you need batteries with Heat, without Heat, with or without Bluetooth
Over the course of 11 years, we have delivered theMakspower lithium battery with Heat and Bluetooth to only one boat. The battery is placed in the cockpit bench and the boat is used in winter.
The other 1,599 boats with Makspower lithium batteries have standard lithium batteries.
Assemble a battery bank of several smaller batteries to get the most robust battery bank possible. More BMSs means a more robust battery.
Make sure that nothing draws current in the boat during winter storage, whether the boat is on land or in the sea and without shore power.
Makspower lithium batteries have a self-discharge rate of max 3% per month. The batteries can be stored for a long time without charging.
A battery monitor that is left on draws some power. Over the course of a winter, it will drain the battery bank. Unplug it for safety's sake.
Turn off the main switch on the plus and minus side. If you are still unsure whether power is going out of the battery bank, lift off the cable on the negative connection.
If the boat is connected to shore power, a float voltage of 13.5 volts is acceptable. Up to 13.8 volts is ok.
Most Victron chargers can be set to Storage mode at 13.25 volts. This is fine.
Makspower lithium batteries can be used down to minus 20 C. You can turn on lights and heaters if you wish.
From zero degrees and above, you can charge your batteries normally.
From zero to minus 10 C you should be careful. The factory accepts charging with 0.05 C down to minus 10 degrees.
This means that a 100 Ah battery can be charged with up to 5 amps down to minus 10C.
A 300 Ah lithium battery bank can be charged with up to 15 amps down to minus 10 C.
Lithium batteries should not be charged below minus 10 C.
BMS, Battery Management System
This is a powerful electronic card built into the battery case.
The BMS is programmed to handle many tasks.
First and foremost, the BMS is a safety solution that monitors and protects the battery in many areas:
* If the temperature is too high, the battery switches off and shuts down the power supply.
* If the current load is too high, the battery is switched off for power in and out.
* In the event of a short circuit, the battery is shut down.
* The BMS balances the cells so that they work synchronously for maximum battery capacity.
* If the charging voltage is too high, the battery is closed, but remember that the rest of the boat's batteries and equipment are not protected against excessive voltage.
* The BMS is designed to withstand voltages up to 70-80 volts.
* When normal values return, the BMS will open the battery for normal operation.
* At low voltage, approx. 10.7 volts, the battery shuts down to protect the cells.
* The BMS comes in different versions and can handle low or high power.
* More batteries and more BMSs means the battery bank can handle more power.
* Consider multiple batteries instead of one large battery with a BMS. You'll get a more robust battery bank that can deliver enough power for a powerful inverter and can be charged quickly.
The BMS is a very important component that makes Lithium Iron Phosphate (LiFePo4) batteries very safe.
Lead-acid batteries do not have similar safety systems.
The BMS does not control any charging sources, whether it is charging from an alternator, solar cell controller or battery charger.
The charging sources control themselves and stop charging when the batteries are full.
The BMS will not shut down unless there is an error.
A fault can be an overload in the form of too much current going into or out of the battery.
Another error can be that the voltage from the charging source is too high. The BMS closes the battery at just over 15 volts.
But it does not stop the charging source from charging further.
You're guaranteed to have a problem with other equipment in the boat and the lead-acid batteries for the starter and bow thruster if the charging source is not closed.
Some are of the opinion that Lithium batteries turn off and cut off power when they are full.
Furthermore, some people assume that the alternator suddenly has nothing to charge and thus breaks down.
This is wrong.
The alternator is always charging for "something". It can be for other batteries and consumption in the boat.
Having supplied Makspower lithium batteries to around 1,600 boats, we have never in practice seen or heard of any examples of dumploads or damage to alternators or other equipment.
We consider this to be a phenomenon in forums and not something to think about in a boat.
Makspower bases its statements on years of use, testing and experience from 1,600 boats in flawless operation.
We create simple yet robust solutions that work year after year.
We believe our statistics speak for themselves.
Building a solid Lithium battery bank is important.
A large battery with a small/weak BMS can be tempting due to its low price.
If you're going to connect an inverter to enjoy the possibilities of a lithium battery only to discover that the battery can't supply enough power for your hairdryer, Nespresso machine or anything else that makes life on the boat a great experience, then you've bought the wrong battery.
Assemble the lithium battery bank from several batteries so that the total BMS capacity to supply enough power for today's and tomorrow's consumption is in place.
Drop in Lithium batteries look like regular batteries. All wiring and electronics are inside the battery case.
Connecting Drop in batteries is like connecting ordinary batteries.
If a battery fails, you still have more left.
Some people build their own batteries. Then you have wires to the BMS and relays on the outside of the batteries.
If a component such as the BMS or a relay fails, the entire battery bank is dead.
If you need support or parts from the manufacturer, it can be a challenge.
Some people build the batteries themselves and think it's affordable and good.
Makspower lithium batteries have been sold by the thousands and have a virtually flawless history from 2013 until now. We prefer to have the wiring, BMS and electronics on the inside of the battery case and not on the outside.
We have challenged the Norwegian Maritime Authority, the consultancy firm and the other parties that have produced the report.
In our opinion, it is so bad that it should not have been published.
It has since been more or less withdrawn and a new report is under development.
In the report from the Norwegian Maritime Authority, they focus on what must happen if the voltage from the alternator takes off and increases uncontrollably.
To prevent the lithium batteries from being exposed to high voltage, they have proposed a combination of solutions to stop the charging of the lithium batteries.
The solution is based on using relay outputs on the Victron BMV 712 battery monitor, setting the maximum voltage in the battery monitor, activating a relay via the output on the BMV 712 monitor, via very thin and vulnerable wires, through the boat and to a relay-controlled switch that cuts the power to the lithium batteries.
We believe that this is an exceptionally ill-considered solution.
A lithium battery has a built-in BMS that shuts down the battery if the voltage gets too high. This is already a safety feature that AGM, GEL and other batteries do not have.
You'll be pretty unlucky if your alternator breaks down and charges at too high a voltage and at the same time the BMS in the batteries breaks down.
The BMS can withstand 70-80 volts but shuts down at approx. 15 volts.
Another point is that the high voltage from the alternator will still be there, exposing the starter and bow thruster battery to high voltage. If there's one thing most people know, it's that lead-based batteries are likely to start gassing, develop oxyhydrogen gas and possibly explode.
The report says nothing about this. If safety is in focus, this must be included in the report.
Electrical equipment in the boat can also be damaged by excessive voltage.
"It seems to us that those who produced the report have not fully understood where the dangers lie. It's not the lithium batteries that are the problem, but the boat's other lead-based batteries and electrical equipment.
Using the very small and fragile relay outputs on the back of the Victron BMV for razor-thin wires and also configuring the battery monitor to activate the relay output is entirely possible. But it's easy to mess up the configuration and have the wires nibbled out or damaged through the boat. Most boats have a tangle of wires and many have no idea what they are for.
In Makspower's opinion, lithium batteries are well equipped to handle high voltages.
What is important is to stop the source of excessive voltage. If the alternator is the problem, stop the engine, unplug the charging lamp and the alternator will not start charging. Now you can start the engine again and get safely to port.
If the alternator starts to charge anyway, disconnect the cable on alternator B+. Start up and drive home.
You have full lithium batteries and enough power for your chartplotter, autopilot and everything you need. The starter battery can start the engine many times.
Makspower has an MP200 alternator that can be switched on and off with a switch on the field current. It is easy to make the equivalent on most alternators.
Lithium Batteries long term charging and tips
Makspower's own demo boat SØNDAG, Oceanis 50, runs on shore power all year round.
This has been the case for 9 years. The batteries are in perfect condition and suffer no distress from this.
Example: When SØNDAG was ashore for ten days, we forgot to connect the shore power charger. With the freezer and fridge still on, the 1200 Ah battery bank ran out. The battery monitor showed that the six-year-old Makspower batteries had delivered 1238 Ah. Even 6-year-old Makspower lithium batteries had no measurable degradation.
The float voltage from the Victron charger is set to 13.5 volts.
Makspower lithium batteries are designed to last for years at 14.4 to 14.6 volts (common when used as a UPS battery bank).
Since we started using Makspower lithium batteries in 2013, we haven't noticed that any of the batteries have deteriorated because they have been more or less permanently connected to shore power.
In our experience, we haven't seen any examples of Makspower batteries being degraded when stored for the winter fully charged.
In our own boat, the batteries have been stored 100% full all year round with shore power. The capacity has not changed measurably.

In the demo boat SØNDAG, we charge with approx. 282 amps despite the voltage being approx. 13.6 volts. The amps drop slightly when the alternators reach operating temperature.
We don't charge with 14.4 volts but to 14.4 volts.
This stops the alternator (and other charging sources) from charging.
The alternator now only charges to the boat's consumption.

In SANDRINA, the boat in Croatia, the screenshot from the VictronConnect app shows how we topped up the battery in a matter of minutes.
Ampere went over 100 at start-up but dropped down to zero ampere (2.8 A) when the voltage approaches 14.4 volts.
Then the battery bank is full. The alternator is still charging, but only for the boat's consumption or for other battery banks such as the starter and bow thruster, if it needs to top up a little there.

All you need to charge the power bank, starter battery and bow thruster batteries is an electronic battery separator such as Victron Argofet or equivalent.
Many boats are originally delivered with an electronic battery separator.
In an electronic battery separator, the voltage drop is minimal. All the battery banks in the boat receive the same voltage when all the batteries are charged.
The starter battery should have almost no power. The bow thruster should perhaps have 10-15 Ah, ampere hours after diligent use.
See attached VictronConnect screenshot from the demo boat SØNDAG. This shows charging to all the battery banks. Power is flowing into the consumer bank and the other batteries are also getting what they need.
In this case, we're charging with Makspower's new MP100 MK2 alternator. It will be available in spring 2025. It charges very solidly and fits most Yanmar engines.
Lithium batteries with Heat and Bluetooth
In boats, you don't normally need lithium batteries with Heat.
Even if the boat is on land in winter, the self-discharge is so low that you don't have to charge in the cold. Lithium batteries with Heat are more expensive than standard lithium batteries without Heat (and Bluetooth).
Save money and buy more batteries instead.
If you buy one battery and have no plans to buy more, it's nice to have a simple app and Bluetooth to keep track of the power situation.
Most people buy one or more batteries. Then the solution with Victron Smartshunt or Victron BMV 712 battery monitors with Bluetooth and the VictronConnect app is a much better solution.
What we're looking for is to monitor the entire battery bank and not each individual battery.
The app that comes with lithium batteries with Bluetooth is simple.
It shows in each individual battery:
* Current (amps) in when charging
* Current (amps) out during consumption
* Voltage
* Temperature in the battery
* AH, ampere hours used
* SOC, State Of Charge in %
In addition, in some apps you can see information about the individual cell groups in the battery. Error codes may also appear.
If you need more than one battery, the VictronConnect app is the right solution. Drop Bluetooth in your batteries and buy Victron Smartshunt or Victron BMV 712 battery monitor. If you expand your battery bank later, Victron battery monitors still cover the entire battery bank.
The VictronConnect app is a highly advanced yet easy-to-use app that covers the entire battery bank.
In VictronConnect, you can set many important parameters to get a perfect reading on the battery bank.
The VictronConnect app takes in all Victron products that have Bluetooth.
Loaders
SmartShunt battery monitor
BMV 712 battery monitor
Solar controllers
Batteryprotect
Control relay outputs
Set an alarm for just about anything you want
The VictronConnect app is free of charge.
The Makspower app is a neat and tidy app that shows you what you need to know. All Makspower lithium batteries with Heat also have built-in Bluetooth.
If you are combining multiple heat Bluetooh batteries, we recommend installing a Vcictron battery monitor and the VictronConnect app.
This gives you an overview of the entire battery bank.
The Makspower app is called Makspower and can be downloaded for free from Playstore or Appstore.
Remember to download the Makspower Heat Bluetooth user guide on the Makspower website.
For the app to work, it must have access to Location Services/Position.
Grant access when you install the app. If you have forgotten, you must grant access under Settings in your phone.
Lithium batteries with Heat are a must if you want to charge your batteries in the cold.
When charging with a generator at sub-zero temperatures, the batteries must first be warmed up, which happens automatically, before the battery can be powered.
A 100 Ah lithium battery has a heating foil that draws 60-70 watts. If you have more batteries, even more power is needed to heat the battery bank.
In practice, this means that solar panels are unlikely to be able to supply enough electricity to heat the batteries.
But there is hope:
Makspower Lithium batteries with Heat and Bluetooth can withstand up to 0.05 C down to minus 10 degrees. This means a maximum of 5 amps per 100 Ah battery.
This means you can recharge your batteries even in relatively cold weather.
Dynamo and charging of lithium batteries
The alternator gets very hot when it's charging, no matter what kind of batteries it's charging.
Half of the energy supplied by the alternator is converted into heat. The rest is used to charge the batteries.
If the alternator is charging at 100 amps, this means that approximately 1,400 watts are going into the batteries and roughly the same amount is going out in heat. Obviously, a relatively small object like a dynamo gets very hot when it has to release so many watts on such a small surface.
It's true that lithium batteries have a very low internal resistance and can accept a lot of current.
It's a myth, however, that lithium batteries almost force the alternator to deliver more power than it's designed for.
An alternator charges as much as it can regardless of the type of batteries it is charging.
Makspower has (as of 2024) delivered Makspower lithium batteries to more than 1600 boats. We have not seen any connection between charging lithium batteries and alternator problems.
Dynamos are very solid. It is rare that we see defective alternators.
No need to worry about the alternator if you install lithium batteries.
Oddly enough, many people have begun to touch the dynamo when it comes to dynamos and lithium batteries.
Our recommendation is to stop touching the alternator. It will do just fine on its own.
If you still need to touch the alternator when it's charging, you can buy barbecue mitts or welding gloves from Makspower or other local suppliers.
It is a common belief that the alternator must be protected with an external voltage regulator when charging lithium batteries.
This is wrong.
The purpose of an external voltage regulator is usually to increase the charge. The Hitachi 80 alternator, which is fitted to many Yanmar engines, charges below 40 amps at operating temperature. With an external voltage regulator, it charges at around 70 amps. This means that it charges considerably more and develops much more heat, which in turn must be dissipated.
Despite the fact that some external voltage regulators have temperature sensors and tables for reducing the charge, the alternator is forced to charge much more than it is designed for.
Therefore, the recommendation to use an external voltage regulator is often a self-motivation if the purpose is to protect the alternator from excessive heat.
No, you don't.
There are no alternators designed specifically for lithium batteries.
An alternator with an internal voltage regulator is pre-programmed to charge to a maximum voltage, which is usually 14.4 volts.
The dynamo will charge everything it can to reach the target.
The resistance in the battery bank will gradually increase and charging will stop when the regulator in the alternator senses 14.4 volts.
A good alternator has an external sensor cable that senses the voltage of the battery bank it is charging.
In other words, an alternator with a sensor cable compensates for the voltage drop from the alternator to the battery bank. Charging is improved and the batteries are fully charged.
An alternator without a sensing lead charges more poorly and the maximum voltage (fully charged battery bank) takes longer if it is fully charged at all.
No, it isn't. It is not necessary.
A dynamo with built-in regulator and external sensing cable is all you need.
This is by far the simplest and best solution and it works.
In many cases, external regulators have an advanced charging profile and adjustable values. You don't need that.
Makspower alternators all have an external sensing lead.
They charge quickly and correctly.
Many other standard alternators also have an external sensing lead.
Yes, you can. You also have no choice when charging with a dynamo.
The alternator charges as much as it can, and the most power goes where there is the least resistance. Starter batteries and the batteries for the bow thruster are usually lead batteries (AGM or GEL).
Almost no Ah (ampere-hours) are used either to start the engine or to use the bow thruster (maybe no more than 10-15 Ah if you're keen).
The starter and bow thruster batteries are quickly charged to full and the lithium batteries for consumption are charged in parallel.
When all the batteries are full, the voltage will be approximately the same on all the battery banks.
There is a misconception that you need to have a DC-DC charger to protect the alternator from getting too hot.
In many cases, you pay more to charge less if you buy a DC-DC charger.
An alternator is designed to charge, and it can do that no matter what it's charging.
Charging lithium batteries is very simple.
Charge until the voltage reaches 14.4 volts at 20 degrees C.
When this voltage is reached, the alternator stops charging. As long as you run the engine and the alternator is charging, the voltage will remain at approximately 14.4 volts on the lithium batteries and all the other battery banks.
Makspower lithium batteries can withstand this voltage for a long time.
AGM and GEL batteries get the same voltage.
In practice, this is a charging profile that only consists of charging to 14.4 volts and nothing more complicated.
A DC-DC charger has different charging profiles and you can determine an absorption time period and float voltage.
It's not something you need.
We've tested this product and it certainly doesn't work as advertised.
Charging five times faster? Is it possible? No, it isn't.
We tested this on a Hitachi 80 alternator which is common on many Yanmar engines. In its original condition, it delivers less than 40 amps at working temperature. With an external regulator for a few hundred dollars, it can charge about 60 amps.
With Alternator for Battery charger, Hitachi should be able to charge closer to 200 amps or more?
We have a council in such matters:
When sounds too good to be true, it usually is.
From the Alternator to Batterycharger commercial:
The Alternator to Battery charger (A2B) connects very simply to an existing alternator(s) and
provides extremely fast and effective charge to the domestic/house bank (5+ times faster
than a stand alone alternator). The A2B achieves this performance by pulling down the
voltage on the alternator by putting a 'load' on it. This low voltage (at high current) is
amplified to a 4 stage charging profile at the domestic bank. Due to the A2B's internal
splitting system there is the option to charge the starter battery too. The starter does not get
advanced charging, it simply gets a sufficient maintenance charge.
VI've studied this video carefully and can actually see that a dynamo burns up quite quickly.
The alternator is a completely normal 70-amp alternator that has been refurbished and rebuilt at a factory in Poland. In other words, there is reason to believe that this is an alternator in very good condition. We contacted the alternator factory and had this confirmed.
We also contacted Victron directly to find out how the alternator was tested. We wanted to get details on the table. We didn't get that.
They only confirmed that if an alternator charges a lithium battery bank of 400 Ah or more, it will burn up. We did not receive any further explanation.
In comparison, we have a 1200 Ah lithium bank in our own boat. It is charged with Hitachi 80 with external regulator, we have charged with (Yanmar) Valeo 125 A alternator and now with Makspower MP 100 MKII alternator. We have been doing this for 8 years and completely trouble free.
How Victron has managed to burn up an alternator is unknown to us. This is not common and in no way represents what you can expect in your boat.
We have pointed out to Victron that they have a great responsibility to provide good information and not scare tactics. No response,
Real life examples
Many people have installed lithium batteries in their boats and many lithium battery banks are 300, 400 and well over 600 Ah (ampere hours). The vast majority use the alternator they already have. We at Makspower have by no means seen any examples like the Victron video. It just works.
One of the latest installations was in an Oceanis 46.1. 1200 Ah Makspower Lithium batteries and Valeo 125 A standard alternator on a Yanmar engine. It works perfectly.
What's the easiest way to get more power in your boat?
Switched to lithium batteries.
Install a Victron battery monitor that is configured for lithium batteries.
Now you can see how much power you use per day and how quickly you can recharge your battery bank.
Start with a suitable size of lithium battery bank. You can expand as the need arises.
Is your alternator charging too slowly? Consider a more powerful alternator.
Lithium batteries and alternator charging are predictable and not dependent on sun or wind.
Map the power consumption in your boat with a Victron battery monitor or equivalent.
A boat with one fridge uses a minimum of 100 Ah per day. If you have two fridges, the consumption is much higher.
The battery monitor gives you the answer. Guessing is inaccurate.
Check how much the alternator is charging and how long you need to charge to replenish the battery bank.
AGM and GEL batteries are impossible to recharge.
Switch to lithium batteries and a powerful alternator.
It can dramatically change your life on the boat and give you the vacation you've long dreamed of.
Makspower has equipped many boats for long journeys.
Current charging sources:
1)Dynamo: Predictable charging regardless of wind and sun. Can charge very quickly.
2)Lithium batteries: Large capacity, can be charged quickly, low weight, reliable, takes up little space.
3) Solar panels: Must have sun, charges poorly with just a little shade, breaks quickly if mounted on deck, mount on rack on the hedge for best results.
Have sufficient solar cell capacity and the boat can run itself. 400 to 600 watts in the sun and without shade is a good start.
Rate:
Wind turbine: charges poorly downwind, creates vibrations and turbulence in the boat, needs a lot of wind to charge.
Towing generator: Charges well at speed and poorly on sway.
Efoy: Expensive to buy, expensive fuel, degrades relatively quickly and expensive service.
Aggregate: Expensive, heavy, lots of service problems. If you have a generator, you need a powerful battery charger to utilize the generator for charging.
Victron Multiplus, Inverter and 230 volts in the boat?
An inverter for generating 230 volts is easy to install and relatively inexpensive. It is connected to the battery bank and usually has 2 pcs. 230 volt outlets.
The inverter can be used to charge PCs, mobile phones, TV power (choose 12 volt TV!), CPAP machines, coffee machines, blow dryers, waffle irons and ordinary household equipment.
The inverter is not part of the boat's 230 volt system.
The inverter must be dimensioned very strongly to use a vacuum cleaner. Vacuum cleaners are the main reason why inverters break down.
On/Off with wired switch or remote control is possible.
An inverter at idle (switched on) consumes approx. 0.5 to 0.7 amps. Switch off when not in use.
Use USB connection for charging mobile phones to save power.
Make sure that the battery bank can supply enough power and that the cables are well dimensioned.
Victron Multiplus is an integrated part of the boat's 230 volt system. Switch on the Multiplus as an inverter and you have 230 volts in all the boat's sockets.
Blow-dry your hair, make coffee and heat hot water at the touch of a button.
Victron Multiplus's power as an inverter is stated in VA, Volt Ampere. Subtract 20% to get the power in watts (at 20 C).
Victron Multiplus also has a powerful built-in battery charger.
The most popular Multiplus:
Victron Multiplus 3000-120 2400 watt 120 amp charger Victron Multiplus 2000- 80 1600 watt 80 amp charger
Share a weak course in country
Adjust the current draw from shore and share a course with others.
A great solution that gives you power and charging from a small shore power course.
Victron Multiplus is the heart of a power solution whether you have a boat, motorhome or cabin
With a solid battery bank, good charging and Victron Multiplus dimensioned for the task, life in the boat takes on a new meaning.
Quality of life
Fountain in the bathroom, Nespresso machine, waffle iron, CPAP machine, toaster for the breakfast table, hot water for a shower or washing up, charge the battery of electric trailer, charge PC, cell phones, use blender, ice maker, hand blender and mixer.
If you have a generator, the Multiplus will charge the battery bank in no time.
Induction cooktop in the boat sounds nice.
First check how many watts an induction cooktop draws. This tells you a lot about which inverter or Victron Multiplus is needed to deliver enough power.
Example Ikea induction top with two zones:
Cooktop with induction zones:
Front: 16 cm - 1400 W, booster 2100 W.
Bak: 16 cm - 1400 W, booster 2100 W.
Voltage: 220-240V.
Connecting power: 3700 W.
Amperage: 1 x 16 A.
Here we see that the induction hob needs a 16-ampere course and can collectively draw more than 4,000 watts.
Anything is possible, but are you willing to buy an expensive Victron Multiplus 12-5000 (4000 watt inverter part), a large lithium battery bank, huge cables and use that much power when you can get by with gas or a moderate inverter and kettle?
Also think about how you're going to recharge your batteries.
If you "must have" induction, buy a loose induction hob and a suitable inverter.
no
A diving compressor has a very powerful and unpredictable start-up current.
Building a power system based on lead-acid or lithium batteries, with inverters and expensive cables is a risky project that will most likely not work.
Use a compressor with a fossil fuel engine or fill the cylinders ashore.
What does it take to install lithium batteries in my boat?
No, you do not need to change the alternator. After 11 years of delivering lithium batteries to more than 1,600 boats, we don't see any tendency for the alternators to have problems.
You might consider upgrading to a more powerful alternator if you want faster charging.
Electronic battery separator, by far the best solution for distributing power to all battery banks regardless of whether you have lithium batteries or not.
Electronic battery separators are installed in many boats from around 2006 and later. Virtually zero voltage drop provides maximum charging.
Victron Argofet is the solution for those who want to upgrade.
Voltage controlled relay SVR: Many boats have this solution. It will not work well enough with lithium batteries for consumption and lead for starting and bow thruster.
You can switch to a voltage-controlled relay made for lithium batteries. Victron Cyrix LI can work and is suitable for outboard motors.
For indoor motors, use an electronic battery separator.
Diode separator: Very common in boats with Volvo engines. There is a voltage drop in a diode separator, heat development and some loss of charge but it will work.
DC-DC charger as battery separator?
Don't. Use an electronic battery separator that unlocks the potential of the alternator and charges all battery banks optimally.
Switches?
Switches 1-2, 1+2 and similar are not suitable for power distribution.
Switch to electronic battery separator.
In forums, many people swear by DC-DC chargers.
The reason for this is that the alternator needs to be protected to prevent it from overheating.
Other arguments are that it's necessary for it to charge better.
Example of why you don't need a DC-DC charger:
Volvo's Mitsubishi 115-amp alternator charges approximately 70 to 75 amps to lithium batteries. It can handle it without any problems.
Why spend almost NOK. 5,000 on a DC-DC charger to reduce the charge to 50 amps?
In other words, pay more to charge less.
Victron Argofet costs approx. 1.700,- distributes power perfectly to all battery banks and the alternator charges to the maximum. That's what you want.
The main rule for the best possible safety:
Use a separate battery for starting.
So you can always start the engine and charge the batteries.
The anchor winch can be powered from the starter battery or the bow thruster battery.
Bow thrusters and stern thrusters must have separate batteries.
Why not run your anchor winch and bow thruster on lithium batteries?
If you hold back the anchor winch, a current draw will occur that is similar to a short circuit. The BMS (electronics in the lithium battery) can shut down the battery for safety reasons.
Start-up current on thrusters/ bow thrusters is also unpredictable and can cause the lithium batteries to shut down when you least want them to.
If you have a large enough lithium battery bank, you can power anything.
In 2024, we delivered a large battery bank to a Sweden Yacht 54. It can run the stern thruster and bow thruster at the same time.
Anything is possible if the budget is big enough.
There are several solutions that can work when installing lithium batteries in your boat.
Makspower has delivered solutions to approximately 1,600 boats.
We see what works.
We have experience of most types of boats, whether they are sailing boats, motorboats with one engine, two engines, 12 and 24 volts.
If you're on Facebook or in other forums, you'll hear all kinds of suggestions for solutions. You can get a little confused.
Our solutions are simple and reliable. Ask us for advice.
Many boats have good cables, well-dimensioned cables and are designed for easy installation of lithium batteries.
In other boats, there is a need for a proper review of cables, electrical connections and upgrading of the electrical system, which is often corroded, undersized, loose connections, no overview, connected incorrectly and not suitable for further safe operation.
Whether you're installing lead-acid or lithium batteries, you need an electrical system that's in order for a safe and enjoyable vacation.
Many people focus on the boat's cables on the + side. When was the last time you checked the minus cable, the one that is screwed into the block and through which all the power in the boat goes?
In other words: check your boat's electrical system thoroughly and get an experienced technician to help you.
You can get tips and guidance from Makspower.
In many boats, simply remove the lead-acid batteries and put the lithium batteries straight back in place.
The main rule is that lithium batteries are for consumption and not for anchor winches or bow thrusters.
If the anchor winch receives power from the consumer bank, connect the winch to the starter battery.
The same can apply to the bow thruster.
The bow thruster should definitely have its own battery and preferably as close to the bow thruster as possible for maximum power.
Check that you are not using a voltage controlled relay, SVR, as a battery separator. Switch to Victron Argofet electronic battery separator or equivalent. You may already have an electronic separator.
Recommended: Replace diode separator with electronic separator.
After an inspection a technician will be able to advise you on the condition of your boat and what should and must be upgraded to install lithium batteries.
In many cases, installation is simple.
In other cases, cables need to be replaced, new cables pulled and cleaned up.
Contact Makspower for guidance on where to start the process. Working side-by-side with a technician will save you time and help you get to know your boat better.
How do I charge the lithium batteries?
Most chargers can charge lithium batteries.
When a lithium battery is empty, it switches itself off.
That's why it's important that the charger can start charging from zero volts. If you connect the charger and turn it on, it will either charge normally or it will not charge.
Find out if the charger is suitable for lithium batteries.
This is typical of a charger that cannot charge from zero volts. Zero volts on the lithium battery terminals occurs when the battery is completely empty. It then shuts down to protect the cells.
Solution: Connect another battery with jumper cables to the lithium batteries. Then the charger will be tricked and start charging.
Even better solution: Switch to a Victron charger. All Victron chargers can charge from zero volts.
The battery is empty and closed. Therefore, there is no voltage on the battery terminals.
Recharge with a Victron charger or the charger you have.
If your charger does not start, connect another battery with jumper cables.
Purchased Victron charger. Then the matter is solved once and for all.
Some Mastervolt chargers have a special feature called "return to bulk".
In some cases, it allows the voltage to drop down to 12.4 volts before the charging cycle starts again. With shore power connected and the charger on, you might think the batteries are full. At 12.4 volts, the lithium batteries are almost full.
Charger with temperature compensation:
This function must be switched off. If it cannot be switched off, the charger is not suitable for lithium batteries.
Charger with pulse charging:
Pulse charging is designed to desulphate lead batteries. This function must be switched off. If it cannot be switched off, switch to a Victron charger or other charger designed for lithium batteries.
Charger too small:
Think about how fast you want to charge your batteries. A small charger takes a long time to charge the batteries.
Long-term charging, float voltage and storage mode:
If the batteries are left on charge for a long time, the charger must run at a float voltage of approximately 13.4 to 13.8 volts.
Storage voltage can be approx. 13.25 volts which is fine.
A maximum voltage of 14.4 volts is required.
The batteries can withstand a little more but the batteries do not get fuller.
If the maximum voltage cannot be adjusted down to 14.4 volts or slightly less, replace the charger.
A 100 Ah (Ampere hours) Makspower battery can receive from approx. 100 to 150 amps per battery, depending on the BMS in the battery.
If you have several batteries, the battery bank can accept the total capacity from all the batteries.
Let's say 100 amps to each battery: 3 x 100 Ah means about 300 amps of charge.
In other words, Makspower lithium batteries are no bottleneck or limitation.
When the boat is docked and there is normal life on board, a good deal of electricity is used.
Examples:
Refrigerator 3 amps on average
TV (12 volt) 3 amps
Heater 3 ampere
Light 4 amps
Approximate consumption approx. 13 amps.
If you have a 15-amp charger and need to charge 200 Ah, it takes a long time. There are only 2 amps left to charge with.
So think about how much power is being used in the background, how much you want to charge overnight or during the day, and how powerful a charger you will need.
Victron IP 22-30 amps charger is by far the most sold. With a 15-amp shunt, there are still 15 amps left to charge with.
With shore power connected, you'll be able to recharge around 300 Ah of lithium batteries within 24 hours.
AGM and GEL batteries are far worse to recharge.
Victron Multiplus is a raw charger and inverter.
Multiplus 1600 charger with 70 amps
Multiplus 2000 charger with 80 amps
Multiplus 3000 charger with 120 amps
In addition, you get a superb inverter.
If you invest in a Victron Multiplus, you'll never regret it.
The charging curve for lithium batteries is simple.
Charge straight up to 14.2 volts or to 14.4 volts.
It's slightly faster if the charger is set to a maximum of 14.4 volts.
Some believe it should be charged with constant current/amperes or constant volts.
Neither part is possible.
Read more about charging in Makspower's articles.
You'll find the answer here.
Makspower lithium batteries can be charged with 0.05 C down to minus 10 degrees.
This means 5 amps per 100 Ah battery.
If you have more batteries, you can charge more.
How to get the most out of solar panels in a boat?
Solar panels on deck and on the hatch garage are common.
The challenge with solar panels on deck is that there are always shadows from sails, booms, kicks, masts and whatever else is blocking the sun.
Regardless of what the manufacturer of the solar panels claims, shadows are a killer when it comes to charging. There are always shadows on decks and hatch covers.
Solar panels on deck are a weak solution
* Solar cells consist of a ceramic material. They crack easily and the small threads in the panel are very quickly damaged when the panels are stepped on or subjected to mechanical stress. Expect a short lifespan and little charging
* If you glue the solar panel to the substrate, you will regret it when the panel needs to be replaced. The gelcoat will be full of Sikaflex that you will never be able to remove. Maybe you can't get hold of a new panel with the same dimensions?
* If you peel and stick the panel, you have damaged the fiberglass.
* Our suggestion: Use Velcro from Biltema and glue the panel in this way. It sits well and you have good opportunities to remove the glue residue and bleach the gelcoat when the panel needs to be removed. No screw holes and glue left over.
This is a great solution. You'll get plenty of sun from morning to evening while sailing. You can also use cheaper aluminum-framed solar panels rather than flexible and semi-rigid panels that often cost more.
You can add more panels in the sun on the deck when you arrive.
We always connect solar panels in parallel in boats. This is because if one panel is shaded, it affects all the solar panels. This is especially important if you install solar panels on the deck.
If you have solar panels on a targa pole, they are less exposed to shade. If you use cables with a slightly solid cross-section, the voltage loss is relatively insignificant whether you connect in series or in parallel.
If a panel breaks in series, the panels close. In parallel, the other panels continue to charge as before.
Yes please, both.
It actually depends on where you are.
In domestic areas, it can be very nice in the sun. But the weather is unpredictable. If it's not sunny for a few days, but just a little cloudy, it charges minimally.
It's not the case that solar panels only charge when there is a little light.
If you're in sunny areas, it's a completely different matter. Then you can rely on good charging.
You know you're charging a dynamo when the engine is running. A powerful alternator can recharge a day's worth of solar panels in a very short time.
Solar panels with half cut are made so that the panel consists of two panels. Solar panels are actually split into two panels.
If a shadow appears on one half, the other half will continue to charge.
We think you're lucky if you only get shade on one half and not the other.
It's a questionable selling point.
Some panels are so-called shade optimized. It can be based on the halfcut principle.
Some panels are said to be double-sided. They catch some light that hits the back of the panel.
It's a questionable solution
A small panel in the sun is better than a large panel in the shade.